diff options
Diffstat (limited to 'os/ports/GCC/ARMCMx/crt0.s')
| -rw-r--r-- | os/ports/GCC/ARMCMx/crt0.s | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/os/ports/GCC/ARMCMx/crt0.s b/os/ports/GCC/ARMCMx/crt0.s index a431dd838..fa92b97ea 100644 --- a/os/ports/GCC/ARMCMx/crt0.s +++ b/os/ports/GCC/ARMCMx/crt0.s @@ -45,7 +45,9 @@ .global ResetHandler
.weak ResetHandler
ResetHandler:
- /* Interrupts globally masked. */
+ /*
+ * Interrupts are globally masked initially.
+ */
cpsid i
/*
* Stack pointers initialization.
@@ -53,9 +55,14 @@ ResetHandler: ldr r0, =__ram_end__
ldr r1, =__main_stack_size__
subs r0, r0, r1
- /* { r0 = main stack low address } */
+ /*
+ * Note that r0 is the main stack low boundary address and process
+ * stack initial top address.
+ */
msr PSP, r0
- /* Early initialization. */
+ /*
+ * Early initialization phase, it is empty by default.
+ */
bl hwinit0
/*
* Data initialization.
@@ -100,11 +107,15 @@ endbloop: strlo r0, [r1], #4
blo bloop
#endif
- /* Switches to the Process Stack. */
+ /*
+ * Switches to the Process Stack and uses a barrier just to be safe.
+ */
movs r0, #CONTROL_MODE_PRIVILEGED | CONTROL_USE_PSP
msr CONTROL, r0
isb
- /* Late initialization. */
+ /*
+ * Late initialization phase, it is empty by default.
+ */
bl hwinit1
movs r0, #0
mov r1, r0
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